PPG sensor and method of operating the same

Abstract

A photoplethysmogram (PPG) sensor includes a pixel array that collects light, a pixel sampler that converts the light collected through the pixel array into a plurality of pixel data, an effective area determiner that determines an effective area and a non-effective area of the pixel array based on the pixel data, a power controller that is operable to cut off power to the non-effective area of the pixel array, and a PPG data generator that generates PPG data from pixel data corresponding to the effective area among the pixel data.

What is claimed is: 
     
       1. A photoplethysmogram (PPG) sensor, comprising:
 a pixel array that collects light; 
 a pixel sampler that converts the light collected through the pixel array into a plurality of pixel data; 
 an effective area determiner that determines an effective area and a non-effective area of the pixel array based on the pixel data; 
 a power controller that is operable to cut off power to the non-effective area of the pixel array; and 
 a PPG data generator that generates PPG data from pixel data corresponding to the effective area among the pixel data, wherein: 
 the effective area determiner sets a first section reference value and a second section reference value based on the pixel data, 
 the effective area determiner includes pixel data, whose values exist between the first section reference value and the second section reference value among the pixel data, in the effective area, and 
 the effective area determiner includes pixel data, whose values do not exist between the first section reference value and the second section reference value among the pixel data, in the non-effective area. 
 
     
     
       2. The PPG sensor as claimed in  claim 1 , wherein the power controller enables rows included in the effective area and disables rows included in the non-effective area by controlling the pixel sampler. 
     
     
       3. The PPG sensor as claimed in  claim 2 , further comprising a timing generator that enables or disables columns of the pixel array, wherein the power controller enables columns included in the effective area and disables columns included in the non-effective area by controlling the timing generator. 
     
     
       4. The PPG sensor as claimed in  claim 1 , further comprising a light amount determiner that determines whether to cut off power based on amounts of light collected for the pixel data, wherein the power controller cuts off power to the pixel array according to a command from the light amount determiner. 
     
     
       5. The PPG sensor as claimed in  claim 4 , wherein the light amount determiner sends a command to the power controller to cut off power to the whole of the pixel array when values of all or at least some of the pixel data exceed a predetermined first light amount reference value. 
     
     
       6. The PPG sensor as claimed in  claim 4 , wherein the light amount determiner sends a command to the power controller to cut off power to the whole of the pixel array when values of all or at least some of the pixel data are less than a predetermined second light amount reference value. 
     
     
       7. The PPG sensor as claimed in  claim 1 , wherein the PPG data generator measures signal quality of the pixel data corresponding to the effective area and continuously generates the PPG data from the pixel data corresponding to the effective area when the signal quality is maintained at a predetermined quality reference value or higher. 
     
     
       8. The PPG sensor as claimed in  claim 7 , wherein the pixel sampler collects light again through the pixel array and generates a plurality of new pixel data when the signal quality measured by the PPG data generator is less than the quality reference value. 
     
     
       9. The PPG sensor as claimed in  claim 1 , wherein the pixel sampler generates the pixel data by collecting light through the pixel array according to a signal generated by a timer. 
     
     
       10. The PPG sensor as claimed in  claim 1 , wherein the pixel sampler generates the pixel data by collecting light through the pixel array according to a signal generated by an external sensor. 
     
     
       11. The PPG sensor as claimed in  claim 1 , wherein the pixel sampler generates the pixel data by collecting light through the pixel array according to a user signal. 
     
     
       12. A photoplethysmogram (PPG) sensor, comprising:
 a pixel array that collects light; 
 a pixel sampler that converts the light collected through the pixel array into a plurality of pixel data; 
 a light amount determiner that determines whether to cut off power based on amounts of the light collected for the pixel data; 
 a power controller that is operable to cut off power to the pixel array according to a command from the light amount determiner; and 
 a PPG data generator that generates PPG data from the pixel data. 
 
     
     
       13. The PPG sensor as claimed in  claim 12 , wherein the light amount determiner sends a command to the power controller to cut off power to the whole of the pixel array when values of all or at least some of the pixel data exceed a predetermined first light amount reference value. 
     
     
       14. The PPG sensor as claimed in  claim 12 , wherein the light amount determiner sends a command to the power controller to cut off power to the whole of the pixel array when values of all or at least some of the pixel data are less than a predetermined second light amount reference value. 
     
     
       15. The PPG sensor as claimed in  claim 12 , further comprising an effective area determiner that determines an effective area and a non-effective area of the pixel array based on the pixel data, wherein the power controller cuts off power to the non-effective area of the pixel array. 
     
     
       16. The PPG sensor as claimed in  claim 15 , wherein:
 the effective area determiner sets a first section reference value and a second section reference value based on the pixel data, 
 the effective area determiner includes pixel data, whose values exist between the first section reference value and the second section reference value among the pixel data, in the effective area, and 
 the effective area determiner includes pixel data, whose values do not exist between the first section reference value and the second section reference value among the pixel data, in the non-effective area. 
 
     
     
       17. The PPG sensor as claimed in  claim 16 , wherein the power controller enables rows included in the effective area and disables rows included in the non-effective area by controlling the pixel sampler. 
     
     
       18. The PPG sensor as claimed in  claim 17 , further comprising a timing generator that enables or disables columns of the pixel array, wherein the power controller enables columns included in the effective area and disables columns included in the non-effective area by controlling the timing generator. 
     
     
       19. A photoplethysmogram (PPG) system, comprising:
 a light source; 
 the PPG sensor as claimed in  claim 1 , the PPG sensor being arranged to receive light, emitted by the light source, that is reflected from skin of a user; and 
 an application receiving PPG data from the PPG sensor. 
 
     
     
       20. A photoplethysmogram (PPG) system, comprising:
 a light source arranged to emit light to skin of a user; 
 a pixel array including pixels, the pixel array being arranged to collect light that is reflected from the skin of the user; and 
 a power controller coupled to the pixel array, and configured to cut off power to a non-effective area of the pixel array while providing power to an effective area of the pixel array, wherein: 
 the effective area of the pixel array contains pixels of the pixel array that correspond to a light amount that is between a first reference value and a second reference value, and 
 the non-effective area of the pixel array contains pixels of the pixel array that correspond to a light amount that is not between the first reference value and the second reference value.